The current level of laboratory instrumentation and computational resources allows X-ray powder diffraction to be implemented into the toolbox of organic chemists, providing a means for rapid (i.e., within a day) structural characterization of organic solids, without the need for single crystals. We illustrate such use of powder diffraction using two case studies of molecular cocrystals of trifluoroacetic acid and malonic acid, involving theobromine, a model active pharmaceutical ingredient. We also report on a previously unobserved conformation of malonic acid in the solid state.